1. Field of the Invention
The present invention relates to a toner used for electrophotographic copiers, facsimiles and printers.
2. Discussion of the Background
Conventionally, a heat fixation is mostly used for fixing a toner. A principle of the heat fixation of a toner is that the toner is softened or melted by a heat of a fixer and enters among fibers of a paper by a pressure of the fixer, or adheres onto the paper due to an adhesive surface of the softened or melted toner. Therefore, a resin used for a toner has to have a melting or softening point lower than the temperature of a fixer.
However, a demand for saving energy for a protection of the global environment is growing recently and an energy consumed for fixing a toner is becoming limited. Practically, the temperature of the fixer has to be decreased in order to decrease the fixing energy. Therefore, a resin for a toner which can be used for a fixer having such a low temperature inevitably has a low melting point. However, a resin having such a low melting point is easily softened and blocked after processed for a toner. In addition, an interaction of the resin with an external additive of a toner changes with age since the surface of the resin is adhesive, resulting in change of properties and poor preservability of the toner. Further, in an image developer, problems such as toner-spent to a carrier in a two-component developer, toner filming over the developing roller and toner adherence to the developing blade occur since the toner is soft and adhesive. Receptor papers even after printed tend to have blocking due to a change of the environment. Besides these problems, there are problems in a process of manufacturing a toner such as low pulverizability and adherence of the toner onto the inside surface of a pulverizer in a pulverizing process because a conventional resin having a low melting point is too soft.
Because of these reasons, a need exists for a toner which does not have the above-mentioned problems.
Accordingly, an object of the present invention is to provide a toner which can be fixed at a temperature lower than that of a conventional toner to save energy, and which have the following properties:
(a) good preservability;
(b) no change of an interaction of a resin included in the toner with an external additive thereof;
(c) no toner-spent, filming and adherence;
(d) imparting good preservability to printed receptor materials; and
(e) good pulverizability.
Briefly this object and other objects of the present invention as hereinafter will become more readily apparent can be attained by a toner capable of fixing at a temperature not greater than a melting point of cyclized polybutadiene which is used as a main binder and dissolved by trans 1,4-polybutadiene at a temperature not less than a melting point thereof.
In addition, the cyclized polybutadiene and the trans 1,4-polybutadiene of the present invention can be substituted by a cyclized rubber and an after-mentioned wax, respectively.